The air space is a busy place, especially near airports or other landing strips, for both pilots and air-traffic controllers. As the air traffic becomes increasingly populated, controllers must efficiently and systematically give instructions via radio to pilots in that heavily populated air space. Similarly, pilots rely on the radio transmissions from the air traffic controllers as a means of increasing safety.
There may be many reasons why a pilot might not clearly receive radio instructions from air traffic controllers such as workload, cockpit noise, weather, other closely spaced aircraft, or any number of other reasons. If the pilot-air traffic controller communications routine is disrupted because a pilot missed a radio instruction, then multiple errors can occur. Not only are there delays because the controller has to repeat his instructions, but other aircraft are vulnerable because that one pilot did not receive instructions in a timely fashion.
Many inventions have addressed this and similar problems. For instance, U.S. Pat. No. 4,369,425 to Anderson et al. teaches a pilot unique transmission radio frequency signal to communicate with the air traffic controllers. The prior art also describes various methods of warning pilots of faulty conditions. U.S. Pat. No. 2,259,123 to Wells et al described a complex system for aircraft instrumentation where a unitary panel of lights would show at a glance, all the aircraft instruments status. U.S. Pat. No. 2,337,535 to Acs Jr., describes a visual warning system activated by an abnormal condition in the aircraft instrument panel. In U.S. Pat. No. 3,582,949 to Forst, discloses an audiovisual warning system activated as a result of a monitored condition in fault. Unfortunately, none of the prior art has sought to exploit the idea of a redundant visual indication to uniquely identify a transmission from air traffic controllers to a given aircraft.
There have been various in home applications of audio signals driving a visual indication. In U.S. Pat. No. 3,798,638 to Goldschmied, an audio responsive display where the lights are modulated to the audio signal is described. In U.S. Pat. No. 3,890,381 to Hopkins, a system for energizing a lamp upon receipt of predetermined acoustic signals such as telephones or alarm clocks is described. These systems employ fixed circuits that cannot be programmed or changed without physically adjusting the receiving circuit components.